We did a lot of work a few years ago looking a translatability of CAT with
different 5'UTRs and always put a polyA tail on. Poly A will increase the
stability in any translation system so it should probably be left on. 3'UTRs
can also affect translation so you might want to consider adding the tails
enzymatically unless you always have the same 3'UTR.
--
Jillian Johnston
Dept. of Biochemistry and Molecular Biology
University of Calgary
Phone (403) 220-3559
Fax (403) 270-0737